Automatic motor-starter.



G. H. WHITTINGHAM & W. G. O'BRIEN. AUTOMATIC MOTOR STARTER. APPLICATIONFILED 00122, 1908.

965,840, Patented July26,1910.

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UNITED STATES ra rnur OFFICE.

GEORGE H. WHITTINGHAM AND WILLIAM C. OTBRIEN, OF BALTIMORE, MARYLAND,

ASSIGNORS TO MONITOR MANUFACTURING COMPANY OF BALTIMORE CITY, A COR-PORATION OF MARYLAND.

AUTOMATIC MOTOR-STARTER.

Original application filed April 9, 1907, Serial No. 367,193. Dividedand this application filed October 2 Serial No. 455,861.

To all whom it may concern:

Be it known that we, GEORGE H. VVi-IIT- Tmenarr and WILLIAM C. OBRIEN,citizens of the United States, residing at Baltimore, in the State ofMaryland, have invented certain new and useful Improvements in AutomaticMotor-Starters, of which the following is a specification.

This invention comprises improvements in automatic controllers forelectric motors of the kind in which the cutting outcf the startingresistance is regulated by the quantity of current flowing in thearmature circuit.

This application is a division of our eopending application, Ser. No.367,193, filed April 9, 1907.

In the accompanying drawing Figure 1 is a side elevation of thecontroller, the circuits being shown diagrammatically and the movableparts being shown in their normal positions, and Fig. 2 is a similarView, illustrating the operation of the mechanism.

Referring to the drawing, 1 represents a metal cross-bar and 2 indicatesa spring hav ing one end secured to a stationary support 3 and itsopposite end connected to aneye 4, which is rigidly attached to thecenter of the cross-bar. The core 5 of an iron clad holding solenoid Ais rigidly secured to the center of the cross bar and projectsdownwardly therefrom, the arrangement being such that when the solenoidis energized the cross bar will be moved downwardly against the actionof the spring. The cross bar normally supports the core 5 and also thecores 6, 7, 8 and 9, of regulating solenoids B, C, l) and E,respectively. The cores 6, 7 8 and 9 are suspended from the cross bar byrods of copper or other non-magnetic metal, indicated at 6, 7, 8 and 9,respectively. These rods are driven into suitable openings in the upperends of the cores, making good mechanical and electrical connectionstherewith, and extend loosely through openings 10 in the cross bar, andare provide" with stops 11 which rest upon the top of the bar. The cores6,7, 8 and 9 are provided with cont-act disks or blocks 6 7 8 and 9 ofsuitable metal, such as copper, having flat lower surfaces, and thesecores are supported so that said contact blocks will be normally heldout of contact with stationary Specification of Letters Patent.

Patented July 26, 1910.

contact steps or blocks 13, 14, 15 and. 16, respectively, having flatcontact surfaces adapted to be engaged by the Hat contact disks on thesolenoid cores.

The line or supply switch for connecting the controlling apparatus andthemotor with the supply circuit is indicated at S, and it is shown withthe two usual terminals 17 and 18 and an auxiliary terminal 19. Thewinding 20 of the holding solenoid A has one of its ends connected by aconductor 21 to the auxiliary terminal 19 and its other end connected byconductors 22 and 35 to the line switch terminal 18, the circuitarrangement being such-that the solenoid A will be energized each timethe line switch is closed and will be denergized as soon as the lineswitch is opened. Thus, the solenoid A will draw the cross head or bar 1downward as soon as the switch is closed and the cross head will remaindown until the switch is opened, when it will be moved upward by thespring 2.

The windings of the solenoids B, C, D and E, are arranged in series withone another and with the starting resistance and with the aru'iature m.of the motor M. These windings are all of low rcsistancein order tocarry the full starting current, and they are all operative for thepurpose of regulating the descent of the solenoid. cores. The circuit istraced as follows: Fro the line switch terminal 17, through conductor23, winding 2i. resistance section 25, winding 20, resistance section27, winding 28, resistance section 29, winding 30, resistance section31. conductor 32. armature m and conductor 35 to line switch terminal18. A shunt winding for the motor field is indicated at 7'. itsterminals bciugcom'icclcd to the line switch terminals by conductors 35and 3t), respectively. The rods 6, 7 8 and 9, are elcctritnll connectedto the terminal 17 of the supply circuit switch by a flexible conductor37 which permits the rods to move indepeinlcntly, said conductor havingone end connected to the conductor leading to the supply circuitswitch.Conductors 38, 39 and 10 connect-the stationary contacts 13, 1% and 15with the coils of the solenoids C, D and E, respectively, at pointsbetween the ends of said coils, and a conductor 1'1 connects thestationary contacts 16 with the conductor 32 leading to the motorarmature. lVhen the line switch S is moved to closed position, thesolenoid A is energized, and its core is immediately drawn downward,thereby moving the cross bar 1 away from the collars on the rods 6, 7-,8 and 9, and placing the spring 2 under tension. The cores of theregulating solenoids, B, C, D

andE, will remain suspended owing to the abnormal quantity of currentflowing in the armature circuit immediately after-the closing of theswitch, the quantity of current I permitted; to flow at the start being,of course, regulated by-theamount of'starting resistance. The solenoidsC, D and E may be all similarly wound, with the same length,

. ofwire, while the solenoid B has a shorter ing greater lengths ofwindings in circuit I at the start,'will not release their cores withthis decrease in current. When the core of the solenoid'B drops,however, it cuts out its own coils, one section, 25, of the resistanceand a part of the windings of the solenoid G, thus weakening the lattersolenoid so that after the temporary rise in the current .whichresultsfrom the cutting out of the resistance section, when the current fallsto a predetermined amount, which maybe the same amount that was flowingwhen the core of the solenoid B dropped, the core of the solenoid C willdrop. This cuts out the remainder of its own coils, the resistancesection 27 and a part of the coils of the next solenoid D, weakening thelatter so that when the current falls as before, the

core of the latter solenoid will drop and cut out the remainder of itsown coils, resistance section 29 and part of the coils of the solenoidE. WVhen the current again falls to a predetermined amount, the solenoidE will release its core and the remainder of its coils and the lastresistance section 31, will be cut out.

The operation of the device in cutting outthe resistance is illustratedin Fig. 2, wherein the line switch is closed, the cross bar moved downand the cores of the first two solenoids, B and C, in the series aredown,

while the cores of the last two solenoids D and E, are still supportedby the action of the current in their coils. hen the core of thesolenoid B dro s, it will be seen that the current, instead 0 flowingthrough its coils and the resistance section 25, will flow from the lineswitch terminal 17 through a low resistance path formed by the flexibleconductor 37, conducting rod 6*, solenoid core 6, contacts 6 and 13, andconductor 38 to a point intermediate the ends of the coils of thesolenoid C, thus short circuiting all of the coils of. the solenoid B,the resistance section 35 and a part of the coils'of the solenoid C.When the core of the solenoid 0 drops, a path for the current will beformed from the flexible conductor 37 through the conducting rod 7, core7, contacts 7 and 14, and conductor 39 to a point intermediate the endsof the winding of the solenoid D, thus-short circuiting the remainingcoils of the solenoid C', the resistance section 27 and part of thecoils of the solenoid D. Similarly, when the core of the solenoidD'drops, the current will flow from the flexible-conductor 37 throughthe rod 8 core 8, contacts 8 and 15, and conductor 40, and when the coreof the solenoid E drops, the current will have a direct low resistancepath to the motor armature from the flexible conductor through the rod 9core 9, contacts 9 and 16 and conductors 4.1 and 32. As soon as the lineswitch is opened to stop the motor, the solenoid A is denergized and thespring moves the cross head 1 upwardly into the position shown inFig. 1. The cores of the solenoids B, C, D and E are thereby moved toseparate the contacts at their lower ends, and the windings of saidsolenoids and the resistance sections areaga-in placed in circuit readyfor tors leading to such rods, it is possible to support the cores fromabove the solenoids and utilize the cores as switch members therebyrequiring but one stationary contact beneath each core.

What we claim is- 1. An automatic starter for electric mois turned on.

5 comprising a starting resistance in the armaabove said contacts and anelectro-magnetic device for releasing said cores when current 2. Anautomatic starter for electric motors ture circuit, a series ofregulatin solenoids having all of their operative windings of lowresistance and arranged in said circuit, shunt circuits for cutting outwindings of each solenoid, a section of starting resistance and a partof the coils of a succeeding solenoid, each of said shunt circuitscomprising a solenoid core, a stationary contact below said core adaptedto be engaged by 5 the core, a conducting rod secured to the

